Most cultivated orchids are native to the tropics. In their natural habitat, they attach themselves to the bark of trees, or the surface of other plants. Their thick, white roots are specially adapted to absorb moisture and dissolved nutrients. Because these tropical orchids usually grow high in the trees, rather than on the forest floor, they are accustomed to good air circulation and plenty of light. They prefer a 12-hour day, all year-round, and require a high intensity of light — about the same as midsummer conditions in temperate regions.